import {
  AddOperation,
  AnimationClip,
  Bone,
  BufferGeometry,
  Color,
  CustomBlending,
  DoubleSide,
  DstAlphaFactor,
  Euler,
  FileLoader,
  Float32BufferAttribute,
  FrontSide,
  Interpolant,
  Loader,
  LoaderUtils,
  MeshToonMaterial,
  MultiplyOperation,
  NearestFilter,
  NumberKeyframeTrack,
  OneMinusSrcAlphaFactor,
  Quaternion,
  QuaternionKeyframeTrack,
  RepeatWrapping,
  Skeleton,
  SkinnedMesh,
  SrcAlphaFactor,
  TextureLoader,
  Uint16BufferAttribute,
  Vector3,
  VectorKeyframeTrack,
} from 'three'
import { TGALoader } from '../loaders/TGALoader'
import { Parser } from '../libs/mmdparser'

/**
 * Dependencies
 *  - mmd-parser https://github.com/takahirox/mmd-parser
 *  - TGALoader
 *  - OutlineEffect
 *
 * MMDLoader creates Three.js Objects from MMD resources as
 * PMD, PMX, VMD, and VPD files.
 *
 * PMD/PMX is a model data format, VMD is a motion data format
 * VPD is a posing data format used in MMD(Miku Miku Dance).
 *
 * MMD official site
 *  - https://sites.google.com/view/evpvp/
 *
 * PMD, VMD format (in Japanese)
 *  - http://blog.goo.ne.jp/torisu_tetosuki/e/209ad341d3ece2b1b4df24abf619d6e4
 *
 * PMX format
 *  - https://gist.github.com/felixjones/f8a06bd48f9da9a4539f
 *
 * TODO
 *  - light motion in vmd support.
 *  - SDEF support.
 *  - uv/material/bone morphing support.
 *  - more precise grant skinning support.
 *  - shadow support.
 */

/**
 * @param {THREE.LoadingManager} manager
 */
class MMDLoader extends Loader {
  constructor(manager) {
    super(manager)

    this.loader = new FileLoader(this.manager)

    this.parser = null // lazy generation
    this.meshBuilder = new MeshBuilder(this.manager)
    this.animationBuilder = new AnimationBuilder()
  }

  /**
   * @param {string} animationPath
   * @return {MMDLoader}
   */
  setAnimationPath(animationPath) {
    this.animationPath = animationPath
    return this
  }

  // Load MMD assets as Three.js Object

  /**
   * Loads Model file (.pmd or .pmx) as a SkinnedMesh.
   *
   * @param {string} url - url to Model(.pmd or .pmx) file
   * @param {function} onLoad
   * @param {function} onProgress
   * @param {function} onError
   */
  load(url, onLoad, onProgress, onError) {
    const builder = this.meshBuilder.setCrossOrigin(this.crossOrigin)

    // resource path

    let resourcePath

    if (this.resourcePath !== '') {
      resourcePath = this.resourcePath
    } else if (this.path !== '') {
      resourcePath = this.path
    } else {
      resourcePath = LoaderUtils.extractUrlBase(url)
    }

    const modelExtension = this._extractExtension(url).toLowerCase()

    // Should I detect by seeing header?
    if (modelExtension !== 'pmd' && modelExtension !== 'pmx') {
      if (onError) onError(new Error('THREE.MMDLoader: Unknown model file extension .' + modelExtension + '.'))

      return
    }

    this[modelExtension === 'pmd' ? 'loadPMD' : 'loadPMX'](
      url,
      function (data) {
        onLoad(builder.build(data, resourcePath, onProgress, onError))
      },
      onProgress,
      onError,
    )
  }

  /**
   * Loads Motion file(s) (.vmd) as a AnimationClip.
   * If two or more files are specified, they'll be merged.
   *
   * @param {string|Array<string>} url - url(s) to animation(.vmd) file(s)
   * @param {SkinnedMesh|THREE.Camera} object - tracks will be fitting to this object
   * @param {function} onLoad
   * @param {function} onProgress
   * @param {function} onError
   */
  loadAnimation(url, object, onLoad, onProgress, onError) {
    const builder = this.animationBuilder

    this.loadVMD(
      url,
      function (vmd) {
        onLoad(object.isCamera ? builder.buildCameraAnimation(vmd) : builder.build(vmd, object))
      },
      onProgress,
      onError,
    )
  }

  /**
   * Loads mode file and motion file(s) as an object containing
   * a SkinnedMesh and a AnimationClip.
   * Tracks of AnimationClip are fitting to the model.
   *
   * @param {string} modelUrl - url to Model(.pmd or .pmx) file
   * @param {string|Array{string}} vmdUrl - url(s) to animation(.vmd) file
   * @param {function} onLoad
   * @param {function} onProgress
   * @param {function} onError
   */
  loadWithAnimation(modelUrl, vmdUrl, onLoad, onProgress, onError) {
    const scope = this

    this.load(
      modelUrl,
      function (mesh) {
        scope.loadAnimation(
          vmdUrl,
          mesh,
          function (animation) {
            onLoad({
              mesh: mesh,
              animation: animation,
            })
          },
          onProgress,
          onError,
        )
      },
      onProgress,
      onError,
    )
  }

  // Load MMD assets as Object data parsed by MMDParser

  /**
   * Loads .pmd file as an Object.
   *
   * @param {string} url - url to .pmd file
   * @param {function} onLoad
   * @param {function} onProgress
   * @param {function} onError
   */
  loadPMD(url, onLoad, onProgress, onError) {
    const parser = this._getParser()

    this.loader
      .setMimeType(undefined)
      .setPath(this.path)
      .setResponseType('arraybuffer')
      .setRequestHeader(this.requestHeader)
      .setWithCredentials(this.withCredentials)
      .load(
        url,
        function (buffer) {
          onLoad(parser.parsePmd(buffer, true))
        },
        onProgress,
        onError,
      )
  }

  /**
   * Loads .pmx file as an Object.
   *
   * @param {string} url - url to .pmx file
   * @param {function} onLoad
   * @param {function} onProgress
   * @param {function} onError
   */
  loadPMX(url, onLoad, onProgress, onError) {
    const parser = this._getParser()

    this.loader
      .setMimeType(undefined)
      .setPath(this.path)
      .setResponseType('arraybuffer')
      .setRequestHeader(this.requestHeader)
      .setWithCredentials(this.withCredentials)
      .load(
        url,
        function (buffer) {
          onLoad(parser.parsePmx(buffer, true))
        },
        onProgress,
        onError,
      )
  }

  /**
   * Loads .vmd file as an Object. If two or more files are specified
   * they'll be merged.
   *
   * @param {string|Array<string>} url - url(s) to .vmd file(s)
   * @param {function} onLoad
   * @param {function} onProgress
   * @param {function} onError
   */
  loadVMD(url, onLoad, onProgress, onError) {
    const urls = Array.isArray(url) ? url : [url]

    const vmds = []
    const vmdNum = urls.length

    const parser = this._getParser()

    this.loader
      .setMimeType(undefined)
      .setPath(this.animationPath)
      .setResponseType('arraybuffer')
      .setRequestHeader(this.requestHeader)
      .setWithCredentials(this.withCredentials)

    for (let i = 0, il = urls.length; i < il; i++) {
      this.loader.load(
        urls[i],
        function (buffer) {
          vmds.push(parser.parseVmd(buffer, true))

          if (vmds.length === vmdNum) onLoad(parser.mergeVmds(vmds))
        },
        onProgress,
        onError,
      )
    }
  }

  /**
   * Loads .vpd file as an Object.
   *
   * @param {string} url - url to .vpd file
   * @param {boolean} isUnicode
   * @param {function} onLoad
   * @param {function} onProgress
   * @param {function} onError
   */
  loadVPD(url, isUnicode, onLoad, onProgress, onError) {
    const parser = this._getParser()

    this.loader
      .setMimeType(isUnicode ? undefined : 'text/plain; charset=shift_jis')
      .setPath(this.animationPath)
      .setResponseType('text')
      .setRequestHeader(this.requestHeader)
      .setWithCredentials(this.withCredentials)
      .load(
        url,
        function (text) {
          onLoad(parser.parseVpd(text, true))
        },
        onProgress,
        onError,
      )
  }

  // private methods

  _extractExtension(url) {
    const index = url.lastIndexOf('.')
    return index < 0 ? '' : url.slice(index + 1)
  }

  _getParser() {
    if (this.parser === null) {
      this.parser = new Parser()
    }

    return this.parser
  }
}

// Utilities

/*
 * base64 encoded defalut toon textures toon00.bmp - toon10.bmp.
 * We don't need to request external toon image files.
 * This idea is from http://www20.atpages.jp/katwat/three.js_r58/examples/mytest37/mmd.three.js
 */
const DEFAULT_TOON_TEXTURES = [
  '',
  '',
  '',
  '',
  '',
  '',
  '',
  '',
  '',
  '',
  '',
]

// Builders. They build Three.js object from Object data parsed by MMDParser.

/**
 * @param {THREE.LoadingManager} manager
 */
class MeshBuilder {
  constructor(manager) {
    this.crossOrigin = 'anonymous'
    this.geometryBuilder = new GeometryBuilder()
    this.materialBuilder = new MaterialBuilder(manager)
  }

  /**
   * @param {string} crossOrigin
   * @return {MeshBuilder}
   */
  setCrossOrigin(crossOrigin) {
    this.crossOrigin = crossOrigin
    return this
  }

  /**
   * @param {Object} data - parsed PMD/PMX data
   * @param {string} resourcePath
   * @param {function} onProgress
   * @param {function} onError
   * @return {SkinnedMesh}
   */
  build(data, resourcePath, onProgress, onError) {
    const geometry = this.geometryBuilder.build(data)
    const material = this.materialBuilder
      .setCrossOrigin(this.crossOrigin)
      .setResourcePath(resourcePath)
      .build(data, geometry, onProgress, onError)

    const mesh = new SkinnedMesh(geometry, material)

    const skeleton = new Skeleton(initBones(mesh))
    mesh.bind(skeleton)

    // console.log( mesh ); // for console debug

    return mesh
  }
}

// TODO: Try to remove this function

function initBones(mesh) {
  const geometry = mesh.geometry

  const bones = []

  if (geometry && geometry.bones !== undefined) {
    // first, create array of 'Bone' objects from geometry data

    for (let i = 0, il = geometry.bones.length; i < il; i++) {
      const gbone = geometry.bones[i]

      // create new 'Bone' object

      const bone = new Bone()
      bones.push(bone)

      // apply values

      bone.name = gbone.name
      bone.position.fromArray(gbone.pos)
      bone.quaternion.fromArray(gbone.rotq)
      if (gbone.scl !== undefined) bone.scale.fromArray(gbone.scl)
    }

    // second, create bone hierarchy

    for (let i = 0, il = geometry.bones.length; i < il; i++) {
      const gbone = geometry.bones[i]

      if (gbone.parent !== -1 && gbone.parent !== null && bones[gbone.parent] !== undefined) {
        // subsequent bones in the hierarchy

        bones[gbone.parent].add(bones[i])
      } else {
        // topmost bone, immediate child of the skinned mesh

        mesh.add(bones[i])
      }
    }
  }

  // now the bones are part of the scene graph and children of the skinned mesh.
  // let's update the corresponding matrices

  mesh.updateMatrixWorld(true)

  return bones
}

//

class GeometryBuilder {
  /**
   * @param {Object} data - parsed PMD/PMX data
   * @return {BufferGeometry}
   */
  build(data) {
    // for geometry
    const positions = []
    const uvs = []
    const normals = []

    const indices = []

    const groups = []

    const bones = []
    const skinIndices = []
    const skinWeights = []

    const morphTargets = []
    const morphPositions = []

    const iks = []
    const grants = []

    const rigidBodies = []
    const constraints = []

    // for work
    let offset = 0
    const boneTypeTable = {}

    // positions, normals, uvs, skinIndices, skinWeights

    for (let i = 0; i < data.metadata.vertexCount; i++) {
      const v = data.vertices[i]

      for (let j = 0, jl = v.position.length; j < jl; j++) {
        positions.push(v.position[j])
      }

      for (let j = 0, jl = v.normal.length; j < jl; j++) {
        normals.push(v.normal[j])
      }

      for (let j = 0, jl = v.uv.length; j < jl; j++) {
        uvs.push(v.uv[j])
      }

      for (let j = 0; j < 4; j++) {
        skinIndices.push(v.skinIndices.length - 1 >= j ? v.skinIndices[j] : 0.0)
      }

      for (let j = 0; j < 4; j++) {
        skinWeights.push(v.skinWeights.length - 1 >= j ? v.skinWeights[j] : 0.0)
      }
    }

    // indices

    for (let i = 0; i < data.metadata.faceCount; i++) {
      const face = data.faces[i]

      for (let j = 0, jl = face.indices.length; j < jl; j++) {
        indices.push(face.indices[j])
      }
    }

    // groups

    for (let i = 0; i < data.metadata.materialCount; i++) {
      const material = data.materials[i]

      groups.push({
        offset: offset * 3,
        count: material.faceCount * 3,
      })

      offset += material.faceCount
    }

    // bones

    for (let i = 0; i < data.metadata.rigidBodyCount; i++) {
      const body = data.rigidBodies[i]
      let value = boneTypeTable[body.boneIndex]

      // keeps greater number if already value is set without any special reasons
      value = value === undefined ? body.type : Math.max(body.type, value)

      boneTypeTable[body.boneIndex] = value
    }

    for (let i = 0; i < data.metadata.boneCount; i++) {
      const boneData = data.bones[i]

      const bone = {
        index: i,
        transformationClass: boneData.transformationClass,
        parent: boneData.parentIndex,
        name: boneData.name,
        pos: boneData.position.slice(0, 3),
        rotq: [0, 0, 0, 1],
        scl: [1, 1, 1],
        rigidBodyType: boneTypeTable[i] !== undefined ? boneTypeTable[i] : -1,
      }

      if (bone.parent !== -1) {
        bone.pos[0] -= data.bones[bone.parent].position[0]
        bone.pos[1] -= data.bones[bone.parent].position[1]
        bone.pos[2] -= data.bones[bone.parent].position[2]
      }

      bones.push(bone)
    }

    // iks

    // TODO: remove duplicated codes between PMD and PMX
    if (data.metadata.format === 'pmd') {
      for (let i = 0; i < data.metadata.ikCount; i++) {
        const ik = data.iks[i]

        const param = {
          target: ik.target,
          effector: ik.effector,
          iteration: ik.iteration,
          maxAngle: ik.maxAngle * 4,
          links: [],
        }

        for (let j = 0, jl = ik.links.length; j < jl; j++) {
          const link = {}
          link.index = ik.links[j].index
          link.enabled = true

          if (data.bones[link.index].name.indexOf('ひざ') >= 0) {
            link.limitation = new Vector3(1.0, 0.0, 0.0)
          }

          param.links.push(link)
        }

        iks.push(param)
      }
    } else {
      for (let i = 0; i < data.metadata.boneCount; i++) {
        const ik = data.bones[i].ik

        if (ik === undefined) continue

        const param = {
          target: i,
          effector: ik.effector,
          iteration: ik.iteration,
          maxAngle: ik.maxAngle,
          links: [],
        }

        for (let j = 0, jl = ik.links.length; j < jl; j++) {
          const link = {}
          link.index = ik.links[j].index
          link.enabled = true

          if (ik.links[j].angleLimitation === 1) {
            // Revert if rotationMin/Max doesn't work well
            // link.limitation = new Vector3( 1.0, 0.0, 0.0 );

            const rotationMin = ik.links[j].lowerLimitationAngle
            const rotationMax = ik.links[j].upperLimitationAngle

            // Convert Left to Right coordinate by myself because
            // MMDParser doesn't convert. It's a MMDParser's bug

            const tmp1 = -rotationMax[0]
            const tmp2 = -rotationMax[1]
            rotationMax[0] = -rotationMin[0]
            rotationMax[1] = -rotationMin[1]
            rotationMin[0] = tmp1
            rotationMin[1] = tmp2

            link.rotationMin = new Vector3().fromArray(rotationMin)
            link.rotationMax = new Vector3().fromArray(rotationMax)
          }

          param.links.push(link)
        }

        iks.push(param)

        // Save the reference even from bone data for efficiently
        // simulating PMX animation system
        bones[i].ik = param
      }
    }

    // grants

    if (data.metadata.format === 'pmx') {
      // bone index -> grant entry map
      const grantEntryMap = {}

      for (let i = 0; i < data.metadata.boneCount; i++) {
        const boneData = data.bones[i]
        const grant = boneData.grant

        if (grant === undefined) continue

        const param = {
          index: i,
          parentIndex: grant.parentIndex,
          ratio: grant.ratio,
          isLocal: grant.isLocal,
          affectRotation: grant.affectRotation,
          affectPosition: grant.affectPosition,
          transformationClass: boneData.transformationClass,
        }

        grantEntryMap[i] = { parent: null, children: [], param: param, visited: false }
      }

      const rootEntry = { parent: null, children: [], param: null, visited: false }

      // Build a tree representing grant hierarchy

      for (const boneIndex in grantEntryMap) {
        const grantEntry = grantEntryMap[boneIndex]
        const parentGrantEntry = grantEntryMap[grantEntry.parentIndex] || rootEntry

        grantEntry.parent = parentGrantEntry
        parentGrantEntry.children.push(grantEntry)
      }

      // Sort grant parameters from parents to children because
      // grant uses parent's transform that parent's grant is already applied
      // so grant should be applied in order from parents to children

      function traverse(entry) {
        if (entry.param) {
          grants.push(entry.param)

          // Save the reference even from bone data for efficiently
          // simulating PMX animation system
          bones[entry.param.index].grant = entry.param
        }

        entry.visited = true

        for (let i = 0, il = entry.children.length; i < il; i++) {
          const child = entry.children[i]

          // Cut off a loop if exists. (Is a grant loop invalid?)
          if (!child.visited) traverse(child)
        }
      }

      traverse(rootEntry)
    }

    // morph

    function updateAttributes(attribute, morph, ratio) {
      for (let i = 0; i < morph.elementCount; i++) {
        const element = morph.elements[i]

        let index

        if (data.metadata.format === 'pmd') {
          index = data.morphs[0].elements[element.index].index
        } else {
          index = element.index
        }

        attribute.array[index * 3 + 0] += element.position[0] * ratio
        attribute.array[index * 3 + 1] += element.position[1] * ratio
        attribute.array[index * 3 + 2] += element.position[2] * ratio
      }
    }

    for (let i = 0; i < data.metadata.morphCount; i++) {
      const morph = data.morphs[i]
      const params = { name: morph.name }

      const attribute = new Float32BufferAttribute(data.metadata.vertexCount * 3, 3)
      attribute.name = morph.name

      for (let j = 0; j < data.metadata.vertexCount * 3; j++) {
        attribute.array[j] = positions[j]
      }

      if (data.metadata.format === 'pmd') {
        if (i !== 0) {
          updateAttributes(attribute, morph, 1.0)
        }
      } else {
        if (morph.type === 0) {
          // group

          for (let j = 0; j < morph.elementCount; j++) {
            const morph2 = data.morphs[morph.elements[j].index]
            const ratio = morph.elements[j].ratio

            if (morph2.type === 1) {
              updateAttributes(attribute, morph2, ratio)
            } else {
              // TODO: implement
            }
          }
        } else if (morph.type === 1) {
          // vertex

          updateAttributes(attribute, morph, 1.0)
        } else if (morph.type === 2) {
          // bone
          // TODO: implement
        } else if (morph.type === 3) {
          // uv
          // TODO: implement
        } else if (morph.type === 4) {
          // additional uv1
          // TODO: implement
        } else if (morph.type === 5) {
          // additional uv2
          // TODO: implement
        } else if (morph.type === 6) {
          // additional uv3
          // TODO: implement
        } else if (morph.type === 7) {
          // additional uv4
          // TODO: implement
        } else if (morph.type === 8) {
          // material
          // TODO: implement
        }
      }

      morphTargets.push(params)
      morphPositions.push(attribute)
    }

    // rigid bodies from rigidBodies field.

    for (let i = 0; i < data.metadata.rigidBodyCount; i++) {
      const rigidBody = data.rigidBodies[i]
      const params = {}

      for (const key in rigidBody) {
        params[key] = rigidBody[key]
      }

      /*
       * RigidBody position parameter in PMX seems global position
       * while the one in PMD seems offset from corresponding bone.
       * So unify being offset.
       */
      if (data.metadata.format === 'pmx') {
        if (params.boneIndex !== -1) {
          const bone = data.bones[params.boneIndex]
          params.position[0] -= bone.position[0]
          params.position[1] -= bone.position[1]
          params.position[2] -= bone.position[2]
        }
      }

      rigidBodies.push(params)
    }

    // constraints from constraints field.

    for (let i = 0; i < data.metadata.constraintCount; i++) {
      const constraint = data.constraints[i]
      const params = {}

      for (const key in constraint) {
        params[key] = constraint[key]
      }

      const bodyA = rigidBodies[params.rigidBodyIndex1]
      const bodyB = rigidBodies[params.rigidBodyIndex2]

      // Refer to http://www20.atpages.jp/katwat/wp/?p=4135
      if (bodyA.type !== 0 && bodyB.type === 2) {
        if (
          bodyA.boneIndex !== -1 &&
          bodyB.boneIndex !== -1 &&
          data.bones[bodyB.boneIndex].parentIndex === bodyA.boneIndex
        ) {
          bodyB.type = 1
        }
      }

      constraints.push(params)
    }

    // build BufferGeometry.

    const geometry = new BufferGeometry()

    geometry.setAttribute('position', new Float32BufferAttribute(positions, 3))
    geometry.setAttribute('normal', new Float32BufferAttribute(normals, 3))
    geometry.setAttribute('uv', new Float32BufferAttribute(uvs, 2))
    geometry.setAttribute('skinIndex', new Uint16BufferAttribute(skinIndices, 4))
    geometry.setAttribute('skinWeight', new Float32BufferAttribute(skinWeights, 4))
    geometry.setIndex(indices)

    for (let i = 0, il = groups.length; i < il; i++) {
      geometry.addGroup(groups[i].offset, groups[i].count, i)
    }

    geometry.bones = bones

    geometry.morphTargets = morphTargets
    geometry.morphAttributes.position = morphPositions
    geometry.morphTargetsRelative = false

    geometry.userData.MMD = {
      bones: bones,
      iks: iks,
      grants: grants,
      rigidBodies: rigidBodies,
      constraints: constraints,
      format: data.metadata.format,
    }

    geometry.computeBoundingSphere()

    return geometry
  }
}

//

/**
 * @param {THREE.LoadingManager} manager
 */
class MaterialBuilder {
  constructor(manager) {
    this.manager = manager

    this.textureLoader = new TextureLoader(this.manager)
    this.tgaLoader = null // lazy generation

    this.crossOrigin = 'anonymous'
    this.resourcePath = undefined
  }

  /**
   * @param {string} crossOrigin
   * @return {MaterialBuilder}
   */
  setCrossOrigin(crossOrigin) {
    this.crossOrigin = crossOrigin
    return this
  }

  /**
   * @param {string} resourcePath
   * @return {MaterialBuilder}
   */
  setResourcePath(resourcePath) {
    this.resourcePath = resourcePath
    return this
  }

  /**
   * @param {Object} data - parsed PMD/PMX data
   * @param {BufferGeometry} geometry - some properties are dependend on geometry
   * @param {function} onProgress
   * @param {function} onError
   * @return {Array<MeshToonMaterial>}
   */
  build(data, geometry /*, onProgress, onError */) {
    const materials = []

    const textures = {}

    this.textureLoader.setCrossOrigin(this.crossOrigin)

    // materials

    for (let i = 0; i < data.metadata.materialCount; i++) {
      const material = data.materials[i]

      const params = { userData: {} }

      if (material.name !== undefined) params.name = material.name

      /*
       * Color
       *
       * MMD         MeshToonMaterial
       * diffuse  -  color
       * ambient  -  emissive * a
       *               (a = 1.0 without map texture or 0.2 with map texture)
       *
       * MeshToonMaterial doesn't have ambient. Set it to emissive instead.
       * It'll be too bright if material has map texture so using coef 0.2.
       */
      params.color = new Color().fromArray(material.diffuse)
      params.opacity = material.diffuse[3]
      params.emissive = new Color().fromArray(material.ambient)
      params.transparent = params.opacity !== 1.0

      //

      params.skinning = geometry.bones.length > 0 ? true : false
      params.morphTargets = geometry.morphTargets.length > 0 ? true : false
      params.fog = true

      // blend

      params.blending = CustomBlending
      params.blendSrc = SrcAlphaFactor
      params.blendDst = OneMinusSrcAlphaFactor
      params.blendSrcAlpha = SrcAlphaFactor
      params.blendDstAlpha = DstAlphaFactor

      // side

      if (data.metadata.format === 'pmx' && (material.flag & 0x1) === 1) {
        params.side = DoubleSide
      } else {
        params.side = params.opacity === 1.0 ? FrontSide : DoubleSide
      }

      if (data.metadata.format === 'pmd') {
        // map, envMap

        if (material.fileName) {
          const fileName = material.fileName
          const fileNames = fileName.split('*')

          // fileNames[ 0 ]: mapFileName
          // fileNames[ 1 ]: envMapFileName( optional )

          params.map = this._loadTexture(fileNames[0], textures)

          if (fileNames.length > 1) {
            const extension = fileNames[1].slice(-4).toLowerCase()

            params.envMap = this._loadTexture(fileNames[1], textures)

            params.combine = extension === '.sph' ? MultiplyOperation : AddOperation
          }
        }

        // gradientMap

        const toonFileName = material.toonIndex === -1 ? 'toon00.bmp' : data.toonTextures[material.toonIndex].fileName

        params.gradientMap = this._loadTexture(toonFileName, textures, {
          isToonTexture: true,
          isDefaultToonTexture: this._isDefaultToonTexture(toonFileName),
        })

        // parameters for OutlineEffect

        params.userData.outlineParameters = {
          thickness: material.edgeFlag === 1 ? 0.003 : 0.0,
          color: [0, 0, 0],
          alpha: 1.0,
          visible: material.edgeFlag === 1,
        }
      } else {
        // map

        if (material.textureIndex !== -1) {
          params.map = this._loadTexture(data.textures[material.textureIndex], textures)
        }

        // envMap TODO: support m.envFlag === 3

        if (material.envTextureIndex !== -1 && (material.envFlag === 1 || material.envFlag == 2)) {
          params.envMap = this._loadTexture(data.textures[material.envTextureIndex], textures)

          params.combine = material.envFlag === 1 ? MultiplyOperation : AddOperation
        }

        // gradientMap

        let toonFileName, isDefaultToon

        if (material.toonIndex === -1 || material.toonFlag !== 0) {
          toonFileName = 'toon' + ('0' + (material.toonIndex + 1)).slice(-2) + '.bmp'
          isDefaultToon = true
        } else {
          toonFileName = data.textures[material.toonIndex]
          isDefaultToon = false
        }

        params.gradientMap = this._loadTexture(toonFileName, textures, {
          isToonTexture: true,
          isDefaultToonTexture: isDefaultToon,
        })

        // parameters for OutlineEffect
        params.userData.outlineParameters = {
          thickness: material.edgeSize / 300, // TODO: better calculation?
          color: material.edgeColor.slice(0, 3),
          alpha: material.edgeColor[3],
          visible: (material.flag & 0x10) !== 0 && material.edgeSize > 0.0,
        }
      }

      if (params.map !== undefined) {
        if (!params.transparent) {
          this._checkImageTransparency(params.map, geometry, i)
        }

        params.emissive.multiplyScalar(0.2)
      }

      materials.push(new MeshToonMaterial(params))
    }

    if (data.metadata.format === 'pmx') {
      // set transparent true if alpha morph is defined.

      function checkAlphaMorph(elements, materials) {
        for (let i = 0, il = elements.length; i < il; i++) {
          const element = elements[i]

          if (element.index === -1) continue

          const material = materials[element.index]

          if (material.opacity !== element.diffuse[3]) {
            material.transparent = true
          }
        }
      }

      for (let i = 0, il = data.morphs.length; i < il; i++) {
        const morph = data.morphs[i]
        const elements = morph.elements

        if (morph.type === 0) {
          for (let j = 0, jl = elements.length; j < jl; j++) {
            const morph2 = data.morphs[elements[j].index]

            if (morph2.type !== 8) continue

            checkAlphaMorph(morph2.elements, materials)
          }
        } else if (morph.type === 8) {
          checkAlphaMorph(elements, materials)
        }
      }
    }

    return materials
  }

  // private methods

  _getTGALoader() {
    if (this.tgaLoader === null) {
      if (TGALoader === undefined) {
        throw new Error('THREE.MMDLoader: Import TGALoader')
      }

      this.tgaLoader = new TGALoader(this.manager)
    }

    return this.tgaLoader
  }

  _isDefaultToonTexture(name) {
    if (name.length !== 10) return false

    return /toon(10|0[0-9])\.bmp/.test(name)
  }

  _loadTexture(filePath, textures, params, onProgress, onError) {
    params = params || {}

    const scope = this

    let fullPath

    if (params.isDefaultToonTexture === true) {
      let index

      try {
        index = parseInt(filePath.match(/toon([0-9]{2})\.bmp$/)[1])
      } catch (e) {
        console.warn(
          'THREE.MMDLoader: ' +
            filePath +
            ' seems like a ' +
            'not right default texture path. Using toon00.bmp instead.',
        )

        index = 0
      }

      fullPath = DEFAULT_TOON_TEXTURES[index]
    } else {
      fullPath = this.resourcePath + filePath
    }

    if (textures[fullPath] !== undefined) return textures[fullPath]

    let loader = this.manager.getHandler(fullPath)

    if (loader === null) {
      loader = filePath.slice(-4).toLowerCase() === '.tga' ? this._getTGALoader() : this.textureLoader
    }

    const texture = loader.load(
      fullPath,
      function (t) {
        // MMD toon texture is Axis-Y oriented
        // but Three.js gradient map is Axis-X oriented.
        // So here replaces the toon texture image with the rotated one.
        if (params.isToonTexture === true) {
          t.image = scope._getRotatedImage(t.image)

          t.magFilter = NearestFilter
          t.minFilter = NearestFilter
        }

        t.flipY = false
        t.wrapS = RepeatWrapping
        t.wrapT = RepeatWrapping

        for (let i = 0; i < texture.readyCallbacks.length; i++) {
          texture.readyCallbacks[i](texture)
        }

        delete texture.readyCallbacks
      },
      onProgress,
      onError,
    )

    texture.readyCallbacks = []

    textures[fullPath] = texture

    return texture
  }

  _getRotatedImage(image) {
    const canvas = document.createElement('canvas')
    const context = canvas.getContext('2d')

    const width = image.width
    const height = image.height

    canvas.width = width
    canvas.height = height

    context.clearRect(0, 0, width, height)
    context.translate(width / 2.0, height / 2.0)
    context.rotate(0.5 * Math.PI) // 90.0 * Math.PI / 180.0
    context.translate(-width / 2.0, -height / 2.0)
    context.drawImage(image, 0, 0)

    return context.getImageData(0, 0, width, height)
  }

  // Check if the partial image area used by the texture is transparent.
  _checkImageTransparency(map, geometry, groupIndex) {
    map.readyCallbacks.push(function (texture) {
      // Is there any efficient ways?
      function createImageData(image) {
        const canvas = document.createElement('canvas')
        canvas.width = image.width
        canvas.height = image.height

        const context = canvas.getContext('2d')
        context.drawImage(image, 0, 0)

        return context.getImageData(0, 0, canvas.width, canvas.height)
      }

      function detectImageTransparency(image, uvs, indices) {
        const width = image.width
        const height = image.height
        const data = image.data
        const threshold = 253

        if (data.length / (width * height) !== 4) return false

        for (let i = 0; i < indices.length; i += 3) {
          const centerUV = { x: 0.0, y: 0.0 }

          for (let j = 0; j < 3; j++) {
            const index = indices[i * 3 + j]
            const uv = { x: uvs[index * 2 + 0], y: uvs[index * 2 + 1] }

            if (getAlphaByUv(image, uv) < threshold) return true

            centerUV.x += uv.x
            centerUV.y += uv.y
          }

          centerUV.x /= 3
          centerUV.y /= 3

          if (getAlphaByUv(image, centerUV) < threshold) return true
        }

        return false
      }

      /*
       * This method expects
       *   texture.flipY = false
       *   texture.wrapS = RepeatWrapping
       *   texture.wrapT = RepeatWrapping
       * TODO: more precise
       */
      function getAlphaByUv(image, uv) {
        const width = image.width
        const height = image.height

        let x = Math.round(uv.x * width) % width
        let y = Math.round(uv.y * height) % height

        if (x < 0) x += width
        if (y < 0) y += height

        const index = y * width + x

        return image.data[index * 4 + 3]
      }

      const imageData = texture.image.data !== undefined ? texture.image : createImageData(texture.image)

      const group = geometry.groups[groupIndex]

      if (
        detectImageTransparency(
          imageData,
          geometry.attributes.uv.array,
          geometry.index.array.slice(group.start, group.start + group.count),
        )
      ) {
        map.transparent = true
      }
    })
  }
}

//

class AnimationBuilder {
  /**
   * @param {Object} vmd - parsed VMD data
   * @param {SkinnedMesh} mesh - tracks will be fitting to mesh
   * @return {AnimationClip}
   */
  build(vmd, mesh) {
    // combine skeletal and morph animations

    const tracks = this.buildSkeletalAnimation(vmd, mesh).tracks
    const tracks2 = this.buildMorphAnimation(vmd, mesh).tracks

    for (let i = 0, il = tracks2.length; i < il; i++) {
      tracks.push(tracks2[i])
    }

    return new AnimationClip('', -1, tracks)
  }

  /**
   * @param {Object} vmd - parsed VMD data
   * @param {SkinnedMesh} mesh - tracks will be fitting to mesh
   * @return {AnimationClip}
   */
  buildSkeletalAnimation(vmd, mesh) {
    function pushInterpolation(array, interpolation, index) {
      array.push(interpolation[index + 0] / 127) // x1
      array.push(interpolation[index + 8] / 127) // x2
      array.push(interpolation[index + 4] / 127) // y1
      array.push(interpolation[index + 12] / 127) // y2
    }

    const tracks = []

    const motions = {}
    const bones = mesh.skeleton.bones
    const boneNameDictionary = {}

    for (let i = 0, il = bones.length; i < il; i++) {
      boneNameDictionary[bones[i].name] = true
    }

    for (let i = 0; i < vmd.metadata.motionCount; i++) {
      const motion = vmd.motions[i]
      const boneName = motion.boneName

      if (boneNameDictionary[boneName] === undefined) continue

      motions[boneName] = motions[boneName] || []
      motions[boneName].push(motion)
    }

    for (const key in motions) {
      const array = motions[key]

      array.sort(function (a, b) {
        return a.frameNum - b.frameNum
      })

      const times = []
      const positions = []
      const rotations = []
      const pInterpolations = []
      const rInterpolations = []

      const basePosition = mesh.skeleton.getBoneByName(key).position.toArray()

      for (let i = 0, il = array.length; i < il; i++) {
        const time = array[i].frameNum / 30
        const position = array[i].position
        const rotation = array[i].rotation
        const interpolation = array[i].interpolation

        times.push(time)

        for (let j = 0; j < 3; j++) positions.push(basePosition[j] + position[j])
        for (let j = 0; j < 4; j++) rotations.push(rotation[j])
        for (let j = 0; j < 3; j++) pushInterpolation(pInterpolations, interpolation, j)

        pushInterpolation(rInterpolations, interpolation, 3)
      }

      const targetName = '.bones[' + key + ']'

      tracks.push(this._createTrack(targetName + '.position', VectorKeyframeTrack, times, positions, pInterpolations))
      tracks.push(
        this._createTrack(targetName + '.quaternion', QuaternionKeyframeTrack, times, rotations, rInterpolations),
      )
    }

    return new AnimationClip('', -1, tracks)
  }

  /**
   * @param {Object} vmd - parsed VMD data
   * @param {SkinnedMesh} mesh - tracks will be fitting to mesh
   * @return {AnimationClip}
   */
  buildMorphAnimation(vmd, mesh) {
    const tracks = []

    const morphs = {}
    const morphTargetDictionary = mesh.morphTargetDictionary

    for (let i = 0; i < vmd.metadata.morphCount; i++) {
      const morph = vmd.morphs[i]
      const morphName = morph.morphName

      if (morphTargetDictionary[morphName] === undefined) continue

      morphs[morphName] = morphs[morphName] || []
      morphs[morphName].push(morph)
    }

    for (const key in morphs) {
      const array = morphs[key]

      array.sort(function (a, b) {
        return a.frameNum - b.frameNum
      })

      const times = []
      const values = []

      for (let i = 0, il = array.length; i < il; i++) {
        times.push(array[i].frameNum / 30)
        values.push(array[i].weight)
      }

      tracks.push(new NumberKeyframeTrack('.morphTargetInfluences[' + morphTargetDictionary[key] + ']', times, values))
    }

    return new AnimationClip('', -1, tracks)
  }

  /**
   * @param {Object} vmd - parsed VMD data
   * @return {AnimationClip}
   */
  buildCameraAnimation(vmd) {
    function pushVector3(array, vec) {
      array.push(vec.x)
      array.push(vec.y)
      array.push(vec.z)
    }

    function pushQuaternion(array, q) {
      array.push(q.x)
      array.push(q.y)
      array.push(q.z)
      array.push(q.w)
    }

    function pushInterpolation(array, interpolation, index) {
      array.push(interpolation[index * 4 + 0] / 127) // x1
      array.push(interpolation[index * 4 + 1] / 127) // x2
      array.push(interpolation[index * 4 + 2] / 127) // y1
      array.push(interpolation[index * 4 + 3] / 127) // y2
    }

    const cameras = vmd.cameras === undefined ? [] : vmd.cameras.slice()

    cameras.sort(function (a, b) {
      return a.frameNum - b.frameNum
    })

    const times = []
    const centers = []
    const quaternions = []
    const positions = []
    const fovs = []

    const cInterpolations = []
    const qInterpolations = []
    const pInterpolations = []
    const fInterpolations = []

    const quaternion = new Quaternion()
    const euler = new Euler()
    const position = new Vector3()
    const center = new Vector3()

    for (let i = 0, il = cameras.length; i < il; i++) {
      const motion = cameras[i]

      const time = motion.frameNum / 30
      const pos = motion.position
      const rot = motion.rotation
      const distance = motion.distance
      const fov = motion.fov
      const interpolation = motion.interpolation

      times.push(time)

      position.set(0, 0, -distance)
      center.set(pos[0], pos[1], pos[2])

      euler.set(-rot[0], -rot[1], -rot[2])
      quaternion.setFromEuler(euler)

      position.add(center)
      position.applyQuaternion(quaternion)

      pushVector3(centers, center)
      pushQuaternion(quaternions, quaternion)
      pushVector3(positions, position)

      fovs.push(fov)

      for (let j = 0; j < 3; j++) {
        pushInterpolation(cInterpolations, interpolation, j)
      }

      pushInterpolation(qInterpolations, interpolation, 3)

      // use the same parameter for x, y, z axis.
      for (let j = 0; j < 3; j++) {
        pushInterpolation(pInterpolations, interpolation, 4)
      }

      pushInterpolation(fInterpolations, interpolation, 5)
    }

    const tracks = []

    // I expect an object whose name 'target' exists under THREE.Camera
    tracks.push(this._createTrack('target.position', VectorKeyframeTrack, times, centers, cInterpolations))

    tracks.push(this._createTrack('.quaternion', QuaternionKeyframeTrack, times, quaternions, qInterpolations))
    tracks.push(this._createTrack('.position', VectorKeyframeTrack, times, positions, pInterpolations))
    tracks.push(this._createTrack('.fov', NumberKeyframeTrack, times, fovs, fInterpolations))

    return new AnimationClip('', -1, tracks)
  }

  // private method

  _createTrack(node, typedKeyframeTrack, times, values, interpolations) {
    /*
     * optimizes here not to let KeyframeTrackPrototype optimize
     * because KeyframeTrackPrototype optimizes times and values but
     * doesn't optimize interpolations.
     */
    if (times.length > 2) {
      times = times.slice()
      values = values.slice()
      interpolations = interpolations.slice()

      const stride = values.length / times.length
      const interpolateStride = interpolations.length / times.length

      let index = 1

      for (let aheadIndex = 2, endIndex = times.length; aheadIndex < endIndex; aheadIndex++) {
        for (let i = 0; i < stride; i++) {
          if (
            values[index * stride + i] !== values[(index - 1) * stride + i] ||
            values[index * stride + i] !== values[aheadIndex * stride + i]
          ) {
            index++
            break
          }
        }

        if (aheadIndex > index) {
          times[index] = times[aheadIndex]

          for (let i = 0; i < stride; i++) {
            values[index * stride + i] = values[aheadIndex * stride + i]
          }

          for (let i = 0; i < interpolateStride; i++) {
            interpolations[index * interpolateStride + i] = interpolations[aheadIndex * interpolateStride + i]
          }
        }
      }

      times.length = index + 1
      values.length = (index + 1) * stride
      interpolations.length = (index + 1) * interpolateStride
    }

    const track = new typedKeyframeTrack(node, times, values)

    track.createInterpolant = function InterpolantFactoryMethodCubicBezier(result) {
      return new CubicBezierInterpolation(
        this.times,
        this.values,
        this.getValueSize(),
        result,
        new Float32Array(interpolations),
      )
    }

    return track
  }
}

// interpolation

class CubicBezierInterpolation extends Interpolant {
  constructor(parameterPositions, sampleValues, sampleSize, resultBuffer, params) {
    super(parameterPositions, sampleValues, sampleSize, resultBuffer)

    this.interpolationParams = params
  }

  interpolate_(i1, t0, t, t1) {
    const result = this.resultBuffer
    const values = this.sampleValues
    const stride = this.valueSize
    const params = this.interpolationParams

    const offset1 = i1 * stride
    const offset0 = offset1 - stride

    // No interpolation if next key frame is in one frame in 30fps.
    // This is from MMD animation spec.
    // '1.5' is for precision loss. times are Float32 in Three.js Animation system.
    const weight1 = t1 - t0 < (1 / 30) * 1.5 ? 0.0 : (t - t0) / (t1 - t0)

    if (stride === 4) {
      // Quaternion

      const x1 = params[i1 * 4 + 0]
      const x2 = params[i1 * 4 + 1]
      const y1 = params[i1 * 4 + 2]
      const y2 = params[i1 * 4 + 3]

      const ratio = this._calculate(x1, x2, y1, y2, weight1)

      Quaternion.slerpFlat(result, 0, values, offset0, values, offset1, ratio)
    } else if (stride === 3) {
      // Vector3

      for (let i = 0; i !== stride; ++i) {
        const x1 = params[i1 * 12 + i * 4 + 0]
        const x2 = params[i1 * 12 + i * 4 + 1]
        const y1 = params[i1 * 12 + i * 4 + 2]
        const y2 = params[i1 * 12 + i * 4 + 3]

        const ratio = this._calculate(x1, x2, y1, y2, weight1)

        result[i] = values[offset0 + i] * (1 - ratio) + values[offset1 + i] * ratio
      }
    } else {
      // Number

      const x1 = params[i1 * 4 + 0]
      const x2 = params[i1 * 4 + 1]
      const y1 = params[i1 * 4 + 2]
      const y2 = params[i1 * 4 + 3]

      const ratio = this._calculate(x1, x2, y1, y2, weight1)

      result[0] = values[offset0] * (1 - ratio) + values[offset1] * ratio
    }

    return result
  }

  _calculate(x1, x2, y1, y2, x) {
    /*
     * Cubic Bezier curves
     *   https://en.wikipedia.org/wiki/B%C3%A9zier_curve#Cubic_B.C3.A9zier_curves
     *
     * B(t) = ( 1 - t ) ^ 3 * P0
     *      + 3 * ( 1 - t ) ^ 2 * t * P1
     *      + 3 * ( 1 - t ) * t^2 * P2
     *      + t ^ 3 * P3
     *      ( 0 <= t <= 1 )
     *
     * MMD uses Cubic Bezier curves for bone and camera animation interpolation.
     *   http://d.hatena.ne.jp/edvakf/20111016/1318716097
     *
     *    x = ( 1 - t ) ^ 3 * x0
     *      + 3 * ( 1 - t ) ^ 2 * t * x1
     *      + 3 * ( 1 - t ) * t^2 * x2
     *      + t ^ 3 * x3
     *    y = ( 1 - t ) ^ 3 * y0
     *      + 3 * ( 1 - t ) ^ 2 * t * y1
     *      + 3 * ( 1 - t ) * t^2 * y2
     *      + t ^ 3 * y3
     *      ( x0 = 0, y0 = 0 )
     *      ( x3 = 1, y3 = 1 )
     *      ( 0 <= t, x1, x2, y1, y2 <= 1 )
     *
     * Here solves this equation with Bisection method,
     *   https://en.wikipedia.org/wiki/Bisection_method
     * gets t, and then calculate y.
     *
     * f(t) = 3 * ( 1 - t ) ^ 2 * t * x1
     *      + 3 * ( 1 - t ) * t^2 * x2
     *      + t ^ 3 - x = 0
     *
     * (Another option: Newton's method
     *    https://en.wikipedia.org/wiki/Newton%27s_method)
     */

    let c = 0.5
    let t = c
    let s = 1.0 - t
    const loop = 15
    const eps = 1e-5
    const math = Math

    let sst3, stt3, ttt

    for (let i = 0; i < loop; i++) {
      sst3 = 3.0 * s * s * t
      stt3 = 3.0 * s * t * t
      ttt = t * t * t

      const ft = sst3 * x1 + stt3 * x2 + ttt - x

      if (math.abs(ft) < eps) break

      c /= 2.0

      t += ft < 0 ? c : -c
      s = 1.0 - t
    }

    return sst3 * y1 + stt3 * y2 + ttt
  }
}

export { MMDLoader }
